7.1.5 @samp{text}

Use the @samp command to indicate text that is a literal example
or ‘sample’ of a sequence of characters in a file, string, pattern, etc.
Enclose the text in braces. The argument appears within single
quotation marks in both the Info file and the printed manual; in
addition, it is printed in a fixed-width font.

To match @samp{foo} at the end of the line,
use the regexp @samp{foo$}.

produces

To match ‘foo’ at the end of the line, use the regexp
‘foo$’.

Any time you are referring to single characters, you should use
@samp unless @kbd or @key is more appropriate.
Also, you may use @samp for entire statements in C and for entire
shell commands—in this case, @samp often looks better than
@code. Basically, @samp is a catchall for whatever is
not covered by @code, @kbd, @key,
@command, etc.

Only include punctuation marks within braces if they are part of the
string you are specifying. Write punctuation marks outside the braces
if those punctuation marks are part of the English text that surrounds
the string. In the following sentence, for example, the commas and
period are outside of the braces:

In English, the vowels are @samp{a}, @samp{e},
@samp{i}, @samp{o}, @samp{u}, and sometimes
@samp{y}.

This produces:

In English, the vowels are ‘a’, ‘e’,
‘i’, ‘o’, ‘u’, and sometimes
‘y’.